Internal Server Error

I can't connect to my Bukkit Server, which is running with Build #2716, but others can! I tried to delete me of the "player" folder! It doesn't helped. Then I tried to delete the full "player" folder and it worked. Now I teleported me to another player and I've the same problem, but i won't delete the folder once again!
I tried now to delete me and the person, who i teleported to from the player folder and it doesnt help -_-

Please help me You are my last hope
And no, a backup isn't a good alternative for me

Code:

2013-03-26 17:14:30 [INFO] MGbeenieboy[/84.56.166.226:51643] logged in with entity id 14401 at ([world] 1183.5, 64.0, 1148.5)
2013-03-26 17:14:30 [INFO] Disconnecting MGbeenieboy [/84.56.166.226:51643]: Internal server error
2013-03-26 17:14:30 [WARNING] Failed to handle packet for MGbeenieboy [/84.56.166.226:51643]: java.lang.ArrayIndexOutOfBoundsException
java.lang.ArrayIndexOutOfBoundsException